1. Field of the Invention
The present invention relates to an image forming apparatus provided with a cleaning device that cleans a charger.
2. Description of the Related Art
There has been known a multicolor image forming apparatus that can be applied to a color printer, color copier, color facsimile, or the like. In such an image forming apparatus, a contact charger uniformly charges a surface of a photosensitive body, and an exposure device emits a laser beam to the surface of the photosensitive body, thereby forming an electrostatic latent image thereon. A developing device develops the electrostatic latent image into a visible toner image. The toner image is then transferred onto recording paper via an intermediate transfer body, and is fixed to the recording paper by a fixing device.
In this type of multicolor image forming apparatus, it is important to uniformly charge the surface of the rotating photosensitive body. In order to uniformly charge the surface of the rotating photosensitive body, there has been proposed to use two contact chargers disposed in contact with the photosensitive body. Specifically, an upstream-side contact charger in the rotation direction of the photosensitive body charges the surface of the photosensitive body, and a downstream-side contact charger eliminates the unevenness of charging of the photosensitive body, thereby making electric potential of the surface of the photosensitive body uniform. However, with this configuration, the downstream-side contact charger becomes contaminated with toner, silica, or the like, over a long time of use. As a result, discharge from the contaminated parts of the charger may be inadequate, and unevenness of charging of the photosensitive body may occur.
To solve this problem, Japanese Patent-Application Publication No. 2001-175057, No. HEI-11-288150, No. 2001-201923, No. 2001-350313, and No. HEI-5-188738 disclose an image forming apparatus which is provided with a cleaning member that cleans off toner, silica, and the like, by bringing a sponge, brush, pad, urethane foam, felt, or the like, into contact with a contact charger.